A conventional planting apparatus of nursery trees shown in JP-S53-138840A (Patent document 1) comprises a guide tube for guiding a nursery tree, an openable element which has a cone shape divided into two pieces and disposed below the guide tube, plates for covering soil which are disposed on both sides of the divided pieces of the openable element. The openable element is stuck into the ground and opened. Subsequently, a nursery tree in the guide tube is dropped into the ground, and the mound of soil is covered by the plates for covering soil.
Another conventional planting apparatus shown in JP-H9-201136A (Patent document 2) comprises a rotation tube, a guide tube which is slidably provided in the rotation tube, an auger which is provided on lower end of the guide tube and openably divided in two parts, and leveling and pressing plate provided on an outer periphery of the rotation tube. The rotation tube, the guide tube and the auger are pushed down while rotating the auger so as to excavate a planting hole on the ground. After pulling up the guide tube and the auger, the auger is opened and a nursery tree is dropped into the planting hole via the guide tube. After pulling up the guide tube and the auger furthermore, the mound of soil around the nursery tree is pressed by the pressing plate.
Still another conventional planting apparatus shown in JP2007-6715A (Patent document 3) comprises a pair of augers each having a cutting bar and moved down while rotating, and a planting tube which is moved up and down and has an openable shutter at lower end thereof. The ground is excavated by rotation of the augers, the planting tube is stuck into the ground, the shutter at a lower of the planting tube is opened, nursery tree is fed, the planting tube is pulled up, and the soil is leveled and pressed by the cutting bars of the augers.
Still another conventional planting apparatus shown in JP2004-33152A (Patent document 4) comprises an auger, a wall protection tube coaxially provided with the auger and a clamp arm which is disposed outward from the tube for clamping a nursery tree. A planting hole is excavated by the auger and simultaneously the tube is pushed into the planting hole. A nursery tree is fed into the tube by rotation of the clamp arm after pulling up the auger, dropped into the excavated hole, and covered with the soil by rotation of the clamp arm after pulling up the tube.